How to Get a Building Permit for a Fourplex or Multiplex in Toronto

By Sara Rahgozar, M.Arch, OAA, Quadrant Architects

Getting a building permit for a fourplex or any other multiplex in Toronto takes seven steps: check the zoning, confirm the Building Code path, put the team together, prepare the drawings, submit, get through plan review, and pass inspections during construction.

The City approves the permit based on your drawings. How complete and code-compliant they are decides whether it clears on the first review or comes back with deficiency notices (the examiner’s list of required corrections) that add weeks or months.

In this guide:

• Step 1: Zoning
• Step 2: Part 9 or Part 3, and whether you need an architect
• Step 3: The team
• Step 4: The drawing package
• Step 5: Submitting
• Step 6: Plan review and timeline
• Step 7: After the permit
• Building Code requirements
• Converting an existing house
• Costs
• FAQ

Step 1: Does your design meet the zoning?

Before your architect starts the full permit drawings, confirm that the proposed design fits every zoning limit in Toronto’s Zoning By-law 569-2013: height, setbacks, lot coverage, building depth, and any site-specific exceptions in Chapter 900. If the design goes over any of these limits, you need a minor variance from the Committee of Adjustment before the City will issue a permit.

Finding a zoning problem after the drawings are done is the most common cause of wasted time and money on Toronto residential projects. For the step-by-step check, see how to check a Toronto property’s zoning. For what fits on a typical lot and when a variance is needed, see building a fourplex in Toronto. For where six units are allowed, see sixplexes in Toronto.

Step 2: Is your multiplex Part 9 or Part 3 of the Building Code?

This decides who can prepare your drawings and how much engineering you need. The Ontario Building Code sorts buildings by size and use, not by how many units they have.

Do you need an architect for a fourplex or sixplex?

Often you do, even under Part 9. A BCIN-registered designer (someone holding a Building Code Identification Number from Ontario’s Ministry of Municipal Affairs and Housing) can design many Part 9 buildings. But the Building Code requires an architect for a residential building when:

• it’s taller than three storeys, or
• its gross floor area is over 600 square metres and one unit sits above another, or
• its footprint is over 600 square metres and it has three or more units.

Gross floor area adds up all the floors above grade. Three floors of just over 200 square metres each puts a stacked three-storey multiplex over 600. Confirm the code path and whether you need an architect before you hire anyone.

Step 3: Who do you need on the team?

For a typical fourplex, you need an architect, a structural engineer, and a land surveyor.

The architect (OAA licensed) prepares the architectural drawings, stamps and seals them, and takes professional responsibility for the design.

The structural engineer (P.Eng.) designs the foundation, framing, and any structural changes. Their drawings have to match the architect’s, and when they don’t, it’s one of the most common reasons examiners send comments back on residential submissions.

The surveyor (OLS licensed) provides the current survey of the property that the permit application requires.

Depending on the project, you may also need a mechanical or electrical engineer, an energy consultant for the Code’s energy requirements, a geotechnical engineer if the soil is a problem, or an arborist if protected trees are affected.

Step 4: What goes into the drawing package?

Your architect and engineers put together three things: the architectural drawings (site plan, floor plans, elevations, sections, an egress plan, and a schedule showing the design meets the zoning), the structural drawings stamped by the engineer, and the supporting documents, including the application form, the survey, and energy compliance forms.

Every drawing has to be to scale, fully dimensioned, signed, and dated. What matters most to you as the owner is that the package is complete and that the architectural and structural drawings agree with each other.

Step 5: How do you submit the application?

You submit it online through Toronto Building Online Services (TBOS). The City has set up self-service submission for multiplex conversions, laneway suites, garden suites, secondary suites, new houses, and new residential units, with automated document checks.

Submit the complete package. An incomplete package gets sent back before a plan examiner ever looks at the design. Missing documents, unsigned forms, or drawings in the wrong format all delay you at this stage.

Step 6: How long does plan review take?

The City’s target for the first technical review of a residential House Stream application is 10 business days. That covers the first review only, not the whole process.

Every round of revisions adds weeks, which is why the first submission matters so much.

Step 7: What happens after the permit is issued?

• Construction has to follow the approved drawings.
• Mandatory inspections happen at set stages: foundation, framing, insulation, plumbing rough-in, electrical rough-in, fire separation, and final occupancy.
• Changing the design during construction may need a revision to the permit.
• Unpermitted work can lead to fines, stop-work orders, and orders to undo finished work.

What does the Building Code require for a multiplex?

Fire separation. New construction needs a 45-minute fire separation between units. Conversions of existing houses can use a lower rating in some cases, such as 30 minutes for a second unit, or 15 minutes if the whole house has interconnected smoke alarms. Either way, the separation has to be continuous between all units, including between floors.

Egress. Each unit needs at least one means of egress, and exit paths have to meet minimum width and travel-distance requirements.

Light and ventilation. Every habitable room needs a minimum window area and operable ventilation. This matters most for basement units, which have specific requirements for window wells and emergency exit windows.

The Code also sets sound ratings (STC) for the walls, floors, and ceilings between units and minimum sizes for bedrooms, kitchens, bathrooms, and living areas, and it requires interconnected smoke alarms in every unit.

What’s different about converting an existing house?

Three things come up at the permit stage that don’t apply to a new build:

• Structure. The existing structure has to be assessed to confirm it can take the changes. Older Toronto homes often have undersized foundations, weak bearing walls, or deteriorated framing.
• Ceiling heights. Every habitable room has to meet the Code’s minimum ceiling height. For a basement unit in an existing house, that’s 1.95 metres (about 6 feet 5 inches). Many older Toronto basements are lower than that, which means underpinning (lowering the basement floor) to make a legal unit.
• Asbestos and lead. Homes built before the 1980s may have asbestos in insulation, tiles, or pipe wrap, and lead paint. Abatement may be needed before work starts.

For the wider trade-offs between converting a house and building new, see building a fourplex in Toronto.

What does the permit stage cost?

Before construction starts, you pay the building permit fee, which is based on the project’s construction value, plus fees for the architect, engineers, and survey. Development charges are waived for up to six units under current City policy. Put these costs in the budget from the start.

Frequently asked questions

How long does it take to get a multiplex building permit in Toronto?

The City’s target for the first review of a residential House Stream application is 10 business days. Realistically, it takes 2 to 4 months from submission to permit in hand, longer if revisions are needed. Drawing preparation before submission usually takes 4 to 8 weeks.

Is a fourplex Part 9 or Part 3 of the Ontario Building Code?

It depends on size, not the number of units. A residential building of three storeys or less with a building area of 600 square metres or less falls under Part 9, which covers most Toronto fourplexes and sixplexes on interior lots. Larger buildings fall under Part 3.

Do you need an architect for a fourplex in Toronto?

Often you do, even under Part 9. The Ontario Building Code requires an architect for a residential building that is taller than three storeys, has a gross floor area over 600 square metres with one unit above another, or has a footprint over 600 square metres with three or more units. Three floors of just over 200 square metres each puts a stacked three-storey multiplex over 600 square metres of gross floor area.

Do I need a minor variance for my multiplex?

Only if the design exceeds a zoning limit under Toronto Zoning By-law 569-2013, such as setbacks, height, lot coverage, or building depth. In that case you need a minor variance from the Committee of Adjustment before a permit can be issued.

Want your permit to clear on the first review?

Permits get held up by zoning problems found late, the wrong code path, and architectural and structural drawings that don’t match. Quadrant Architects is an OAA-licensed firm in Toronto. Send us the address and what you want to build, and we’ll check the zoning and confirm the code path before any drawings are done.

Call 416-835-0053 or see our residential architecture services. For the full picture on what you can build on a Toronto residential lot, start with our multiplex architect guide for Toronto.

Sara Rahgozar, M.Arch, OAA, Principal, Quadrant Architects

Current as of 2026. Permit processes and fees change, so check current requirements and fee schedules with Toronto Building Customer Service or the City of Toronto website before you apply.

When the Structure Is the Architecture: Exposed Steel at an Industrial Entrance

By Farzad Esnaashari, M.Arch, OAA, Quadrant Architects

In many buildings, the steel that holds everything up stays hidden behind cladding, drywall, and finishes. But on the right project, that steel can do more than carry load. It can become the architecture. That is the idea behind the entrance we designed in 2025 for an industrial building at 1200 Denison Street in Markham, and the subject of a presentation we gave with our structural engineer on the structural consequences of architectural decisions.

Here’s what architecturally exposed steel is, why it changed this building, and why one line in the drawings matters more than most people expect.

How can a small entrance change a whole building?

By changing the first thing anyone sees. The building at 1200 Denison started with a familiar problem: a functional but visually heavy entrance. Masonry columns, a solid canopy, and very little glass made an entry that did nothing to express the building or improve the experience of arriving at it.

The response was not to add decoration. It was to clarify the architecture. We replaced the weight with transparency: exposed structural steel, full-height glazing, and a light canopy that together make a transparent industrial gateway. The intervention is small compared to the building behind it, but it changes how visitors understand and approach the whole place. A new identity does not always require redeveloping the building. A focused change at the point of arrival can do most of the work.

What is architecturally exposed structural steel (AESS)?

Architecturally exposed structural steel, or AESS, is steel that is left visible on purpose and detailed to be looked at, not just to carry load. Ordinary structural steel only has to be strong. AESS has to be strong and good-looking, because people see it up close, which means the bolts, the edges, and the connections all become part of how the building looks.

At 1200 Denison, the steel frame is intentionally visible. The feature columns are six-inch-square hollow steel sections, what the trade calls a 6×6 HSS, standing right beside the doors. The canopy reaches out up to about nine feet over the entry on a light steel frame, held up by slim diagonal braces you can see from the street. Those braces are designed to work in both tension and compression, meaning they can both pull and push, which is how the canopy stays this thin and still holds. The steel carries the canopy and the glazing, but it also gives the entrance its order, rhythm, and character. The structure is on display because it is part of the design.

Why does exposed steel come in different grades?

Because you do not look at all of it the same way. Steel you can only see from the ground, far below a canopy, does not need the same finish as a column standing an arm’s length from the front doors. The industry handles this with AESS categories, a tiered system where a higher category means tighter standards for how the steel is fabricated and finished.

On this project, two categories applied:

How good exposed steel has to look depends on how close people get to it. A connection that is perfectly acceptable high above a canopy may not be acceptable at eye level beside the entrance doors. The point is to spend the effort where it shows — the steel people stand next to gets the smooth welds and clean edges; the steel overhead or far off doesn’t need it.

Where do these projects go wrong?

At the joints, and in the documents. The spot that takes the most work to get right on an exposed-steel entrance is usually where the steel, the glass, and the weatherproofing all come together in one connection. At 1200 Denison, the canopy beam connects to a feature column through a thermal break, an insulating layer that stops cold from transferring through the steel from outside to inside. The drawings call for that connection to be rigid, so it still holds the canopy firmly with the insulating layer in the middle. That single connection is where architectural appearance, structural load, thermal performance, and fabrication quality all converge at once.

So which standard applies to the bolts, the end plates, and the exposed edges right at that transition, the higher one or the lower one? That cannot be left to chance on the shop floor. The line between AESS categories has to be drawn clearly in the contract documents and the shop drawings, and the sensitive connection details have to be reviewed before fabrication starts. As we said in the presentation: “If the documents do not show the line between AESS categories, the shop will draw it.” And the shop’s job is to fabricate efficiently, not to decide how a connection should look beside the front doors.

Why does an entrance this simple take so much coordination?

Because simple to look at is not simple to build. The entrance is meant to look clean and effortless. Pulling that off meant getting the steel, the glass, the canopy, and the weatherproofing to come together without any one of them spoiling the look.

• Exposed steel framing
• Curtain wall glazing (the full-height glass-and-aluminum wall system)
• The canopy structure
• The building enclosure
• Thermal breaks
• Flashing and drainage
• Structural connections
• Foundation design
• Fabrication and installation tolerances

That’s the difference between industrial architecture that’s actually thought through and the kind that just has some steel stuck on for looks. The simple appearance isn’t because there’s less going on — it’s because all of it was worked out ahead of time. When the steel is exposed, there’s nowhere to hide a sloppy joint, so the architect, the engineer, and the fabricator have to be on the same page from day one.

The takeaway for an existing building

A small entrance structure can have a large architectural impact. At 1200 Denison, a compact steel-and-glass intervention gave an existing industrial building a clearer, lighter, and more contemporary identity, without redeveloping the building behind it. The structure is visible because it is part of the architecture, and it works because the architectural intent and the structural reality were coordinated as one thing rather than handed off in sequence.

That is how we approach industrial and commercial architecture generally: the structure, the enclosure, and the details treated as a single design problem. You can see the built result on the 1200 Denison Street industrial entrance project, and more of our work as an industrial architect and in commercial architecture across Ontario.

Farzad Esnaashari, M.Arch, OAA, Quadrant Architects. 416-835-0053 · farzad@quadrantarchitects.com

Based on the joint presentation “AESS, Thermal Breaks, and the Structural Consequences of Architectural Decisions,” by Farzad Esnaashari, M.Arch, OAA, Quadrant Architects, and Farid Rezaeian, Ph.D., P.Eng., SAZAN Inc.

The 2+1: How to Get Three Homes From One Toronto Lot

By Farzad Esnaashari, M.Arch, OAA, Quadrant Architects

If you own a single detached house in an established Toronto neighbourhood, you have more options than you probably realize. One of the most useful is turning one house into three homes: a two-unit duplex with a separate garden suite in the backyard. On a single lot, that is three independent homes, what people call a 2+1.

We recently finished one on Kilbarry Road, in the Avenue Road area. Here is who the 2+1 suits, why you might choose it over other options, and what to check before you start.

What is a 2+1?

A 2+1 is a two-unit duplex in the main house plus one garden suite (or laneway suite) at the back of the lot. Two homes in the house, one in the backyard, three in total. The duplex follows Toronto’s multiplex rules, and the backyard suite follows its own separate rules, which is why it does not count against the units in the main house. The two permissions stack on one lot.

How each piece works, the multiplex units and the garden suite rules, is covered in our separate guides. This one is about the bigger question: whether a 2+1 is the right move for your property, and why.

Who does a 2+1 suit?

It tends to fit three situations well.

The multi-generational family. Parents in one duplex unit, adult children or aging parents in the other, and the garden suite as a private space for a caregiver, a grown child moving back, or grandparents who want their own place with family close by. Three homes, one property, everyone with their own front door.

The owner who wants to live well and earn income. Live in one unit, rent the other and the garden suite, and that income helps carry the property. In an expensive neighbourhood, it can be what makes staying in the area possible.

The long-term investor, who looks at an aging house on a good lot and sees that three rental homes on one well-located property is a more flexible asset than one tired house.

Why choose a 2+1 over a fourplex or sixplex?

More units are not always the right answer. In our experience, a 2+1 has real advantages over packing in the maximum.

The homes are bigger and more livable. Two duplex units plus a proper garden suite gives you three generous spaces instead of four to six smaller ones squeezed into the same building. If you plan to live in one of them, that size and quality usually matters more than the unit count.

The garden suite also gives you something a fourplex cannot: a fully separate home, detached from the main house, with its own entrance and its own bit of yard. For family, or for a higher-end rental, that separation is worth a lot.

And a 2+1 stays in scale with an established street. In a neighbourhood of detached houses, a renovated duplex with a quiet garden suite behind it looks like a home, not a development. For a lot of owners around Avenue Road, Forest Hill, or Lawrence Park, fitting the street is part of the point.

Does a 2+1 work in a high-end established neighbourhood?

It can, and that is a big part of the appeal. The worry owners raise in these areas is always the same: will adding units cheapen the property or clash with the street? Done well, it does not have to. The main house can be renovated to a high standard, the way we did on Kilbarry Road, where a blend of traditional and modern keeps the solid, well-built feel of an older home. The garden suite sits quietly at the back, off the street entirely. From the front, you see one well-kept house, and the three-home layout is not obvious.

What should you check before planning a 2+1?

A few things decide whether a 2+1 works on your lot:

• Lot depth. A garden suite needs room at the back, behind the house, with the required setbacks. A shallow lot may not have it.
• Laneway or not. If your lot backs onto a public laneway, the backyard home is a laneway suite instead of a garden suite, with slightly different rules.
• Access to the rear. The backyard suite needs service connections and fire department access to the back yard.
• The main house. Turning an existing house into a duplex can mean structural, fire-separation, and systems work, especially in an older home.
• Development charges. Toronto currently waives development charges for projects of up to six units, so a three-home 2+1 generally falls within that range. Confirm how the waiver applies to your project, since it can depend on your total unit count and whether you are converting or building new.

Most of this can be settled in an early feasibility review, before you commit to a design or a purchase. That review is where we start on a project like this, as a multiplex architect working across Toronto’s established neighbourhoods, including the Avenue Road area, Forest Hill, Lawrence Park, Midtown, and North Toronto.

Farzad Esnaashari, M.Arch, OAA, Quadrant Architects. 416-835-0053 · farzad@quadrantarchitects.com

Current as of August 2026. Zoning and development charge rules change. Verify the rules for your specific address through the City of Toronto before making design or investment decisions.

Laneway and Garden Suites in Toronto: Adding a Home in Your Backyard

By Sara Rahgozar, M.Arch, OAA, Quadrant Architects

On top of the units you can build in your main house, Toronto lets you add one more home in a separate structure in the backyard. It is the unit that takes a fourplex to five homes, or a sixplex to seven, on a single lot.

There are two kinds: the laneway suite and the garden suite. Which one you can build comes down to a single question, whether your lot backs onto a public laneway. This guide covers both, and how they stack on top of your multiplex units.

What is the difference between a laneway suite and a garden suite?

It is the laneway. If your lot backs onto a public laneway, you build a laneway suite, which faces the lane and is entered from it. Permitted city-wide since July 16, 2019, under the Changing Lanes initiative. If your lot has no laneway, you build a garden suite, which sits in the rear yard. Permitted city-wide since February 2, 2022.

Both are self-contained detached homes, secondary to the main house, and both are allowed in the R, RD, RS, RT, and RM residential zones. You can build one or the other, never both, because Toronto permits one accessory dwelling unit per lot.

How do they stack with a multiplex?

The backyard suite is a separate permission from the multiplex by-law, so it does not count against your main building’s units.

• Anywhere in the city: four units in the main building plus one backyard suite, for five homes on one lot.
• In the nine sixplex wards: six units in the main building plus one backyard suite, for seven homes on one lot.

The main building follows the multiplex rules; the backyard suite follows its own, either the Changing Lanes by-law for laneway suites or the garden suite provisions. Two rule sets apply on the same lot, so confirm the combined unit count and envelope with the City.

Laneway suite and garden suite rules, side by side

The two are close in most respects. Here is how they compare.

Laneway suite specifics

The lot has to abut a public laneway, one the City maintains, not a private drive. The suite entrance must be within 45 metres of a public street along the lane, or 90 metres via the main house, and there has to be a clear path at least 0.9 metres (3 feet) wide to the entrance. Setbacks from the laneway and neighbouring properties apply. The 2025 housekeeping update (Laneway By-law 847-2025, adopted July 24, 2025) aligned the laneway rules with provincial Ontario Regulation 462/24.

Garden suite specifics

The rear yard needs adequate access, including fire department access. A garden suite cannot be severed from the main lot or sold separately under current zoning. One local rule to watch: in parts of the former Etobicoke, including Mimico, New Toronto, Long Branch, and Islington, garden suites carry a 30-metre minimum lot-depth consideration that does not apply the same way elsewhere. Etobicoke lots are often wide and deep, but a shallow one can be disqualified before you start, so confirm your lot depth against the current rule first.

Do you pay development charges on a backyard suite?

It depends on your total unit count across the lot. If the total, main building plus the suite, is six or fewer, development charges are fully waived, the suite included. If the suite brings you to seven or more, it is no longer exempt, but you can apply to defer the charge, and it is waived only if you keep the suite as a rental for 20 years or more. You can build the suite before, after, or alongside the multiplex without affecting the waiver on the main building’s units.

What does a backyard suite cost to build?

Laneway and garden suites typically run $300 to $400 or more per square foot, depending on site conditions, finishes, and how the project is managed. For the same amount of space, that is roughly half the all-in cost of a downtown Toronto condo. A well-located two-bedroom laneway suite rents for about $3,000 to $3,300 a month at current rates.

A few things drive cost beyond the building itself: running water, sewer, electrical, and gas to the back of the lot, which means trenching through an established yard; protected trees in the build zone, which can require an arborist report and can limit where you build; soil conditions, especially with a high water table or fill; and getting materials and equipment to the rear of the lot through a narrow side yard or lane.

Are there loans for building one?

Yes. The City has introduced financing to support backyard suites: loans of $80,000 at 2 percent interest for a basement, garden, or laneway suite, announced for 2025, and up to 90 percent loan-to-value financing that includes the added value of the new suite, which means many owners can build with little out of pocket. Check current availability and eligibility with the City and your lender.

Are there pre-approved plans?

Yes, and they can save time and money. The City has released free pre-approved garden and laneway suite plans, already reviewed for code compliance, which shortens the permit process. It has also enabled self-service permit submissions for laneway suites, garden suites, multiplex conversions, secondary suites, and new houses, and published demonstration plans showing where these can be built across the city.

How do you know your lot qualifies?

For a laneway suite, confirm that your rear or side lot line abuts a public laneway, that you can meet the distance and path-width rules above and the setbacks from the laneway and property lines, and that the build zone is free of protected trees.

For a garden suite, confirm that your lot has no public laneway, that it is deep enough to hold the suite behind the main house with the required setbacks (including the 30-metre depth consideration if you are in Etobicoke), that there is fire department access to the rear yard, and that the build zone is clear of protected trees and other obstructions.

Once the applicable points check out, the next step is a conversation with an architect or a BCIN-qualified designer. It is part of what we do as a multiplex architect.

Sara Rahgozar, M.Arch, OAA, Quadrant Architects. 416-357-5713 · sara@quadrantarchitects.com

Current as of August 2026, reflecting the 2025 housekeeping updates (By-laws 847-2025 and 849-2025) and alignment with Ontario Regulation 462/24. Rules and financing programs change. Verify current requirements through the City of Toronto before making design or investment decisions.

Sixplexes in Toronto: The Nine Wards Where You Can Build Six Units

By Sara Rahgozar, M.Arch, OAA, Quadrant Architects

In nine Toronto wards, you can now build up to six units on a single residential lot, as-of-right, with no rezoning and no hearing. It is one of the biggest steps in the city’s housing reforms, and it opens up options a fourplex cannot.

However, this six-unit permission applies in nine wards only. Everywhere else, the maximum is still four units. So if you are considering a fiveplex or sixplex, the first thing to check is whether your lot is in one of the nine. This guide covers where the permission applies, how it differs from the fourplex rules, and what to confirm before you plan for six.

Where are sixplexes allowed?

On June 25 and 26, 2025, City Council adopted the amendments allowing up to six units as-of-right, through OPA 818 and Zoning By-law 654-2025. The permission covers two areas.

The first is the Toronto and East York district, roughly the area south of Eglinton Avenue, from Roncesvalles in the west to the Beaches in the east. That takes in Cabbagetown, Leslieville, Riverdale, Parkdale, Liberty Village, the Annex, the south end of Leaside, and much of downtown. Eight wards in total.

The second is Ward 23, Scarborough North, from Midland Avenue west to Morningside, south of Highway 401. It was approved earlier, on February 5, 2025, and took effect immediately because no appeals were filed.

That makes nine wards. Everywhere else, four units remains the ceiling.

What if your lot is not in one of the nine wards?

Your maximum is four units, unless your ward councillor opts in. A councillor can ask Council to extend the permission to their ward, and Council votes on it. The list may grow over time, but until your ward is actually added, you cannot design for six units and expect a permit.

Why only nine wards? It became a political question with money attached. In March 2025 the federal Housing Minister warned that if Toronto did not allow sixplexes city-wide by June 30, 2025, Ottawa would hold back 25 percent, roughly $30 million, of the city’s annual Housing Accelerator Fund money. Council approved the nine-ward version anyway, and the funding question is still playing out. For anyone building, the takeaway is simple: check your ward before you design for six.

How is a sixplex different from a fourplex?

Less than you would expect. Under the zoning by-law, a five or six-unit building is a “detached houseplex,” not an apartment building, which the by-law defines as seven units or more. That keeps a sixplex under the ordinary residential rules for height, setbacks, and lot coverage, rather than the tougher rules apartment buildings face.

A few points are worth drawing out:

• Same envelope, more units. A sixplex fits the same height, setback, and lot coverage limits as a fourplex. You are adding units inside the same building size, not getting a bigger building.
• A cap on total bedrooms. The City has set a bedroom cap per building, not per unit. It limits how large your units can be when you go for six, so confirm the cap for your zone and ward.
• Detached only. The six-unit permission is for detached houseplexes. A semi-detached house does not get the same right.
• No parking required, the same as the rest of the multiplex rules.

Can you add a seventh home?

In the nine wards, yes. You can build a six-unit main building plus one laneway or garden suite in the backyard, for seven homes on one lot. This is the “6+1.”

The backyard suite runs under its own rules, not the multiplex by-law, and you can have only one, a laneway suite or a garden suite, never both. If your total across the lot is six units or fewer, development charges are fully waived. If the suite brings you to seven, it is no longer exempt, but you can apply to defer the charge, which is waived only if you keep the suite as a rental for 20 years or more. You can build it before, after, or alongside the main building without affecting the waiver on the main units.

What do people get wrong about sixplexes?

Four beliefs cause most of the confusion:

• “Sixplexes are legal everywhere in Toronto.” Nine wards only, plus any that opt in. Everywhere else the maximum is four.
• “I can build one on my semi-detached lot.” The permission is for detached houseplexes. Semis follow different rules.
• “Six units means a bigger building.” The envelope is the same as a fourplex. Six units means more, smaller units in the same volume.
• “It will go city-wide soon.” That is a political call, not a certainty. Do not design or buy on a rule that does not exist yet for your lot.

What do sixplexes save you financially?

The development charge waiver is the big one. For buildings of up to six units, the City waives development charges entirely. Without it, a six-unit building would face roughly $240,000 to $330,000 in charges, at $40,000 to $55,000 per unit. The City has also frozen development charge rates for 2025 and 2026, and non-rental residential charges are now due at occupancy rather than at permit, effective November 3, 2025, which helps cash flow. The full financial picture is covered in our separate guide to multiplex costs.

How do you confirm your lot qualifies?

Before designing a five or six-unit building, confirm all of these:

• The lot is in one of the nine wards, or a ward that has since opted in
• It is in a residential Neighbourhoods zone (RD, RS, RT, or RM)
• The building is a detached houseplex, not a semi-detached or townhouse
• There is no Chapter 900 site-specific exception adding restrictions
• The lot can physically hold six units within the height, setback, and coverage limits
• Any heritage designation does not block your plans

An architect or designer experienced in Toronto multiplex work can run this review, and many offer a preliminary feasibility check for a modest fee. On a six-unit project it is worth doing before you commit to full design, and it is where we start as a multiplex architect.

Sara Rahgozar, M.Arch, OAA, Quadrant Architects. 416-357-5713 · sara@quadrantarchitects.com

Current as of August 2026. The sixplex ward list can expand through councillor opt-ins, so check with the City of Toronto for the current list. Verify the rules for your specific address before making design or investment decisions.

Building a Fourplex in Toronto: What You Can Build Without a Variance

By Sara Rahgozar, M.Arch, OAA, Quadrant Architects

If you own a house in Toronto, you can now put up to four units on your lot, a duplex, triplex, or fourplex, without a rezoning, a hearing, or a public meeting. City Council made this legal city-wide on May 10, 2023. It is one of the biggest changes to what a homeowner can do with their property in decades.

But there is a catch worth understanding before you get excited or spend money on drawings. “Allowed” comes with a set of limits on the size and shape of the fourplex you can build. Stay inside those limits and your project goes straight to a building permit. Break even one of them and you are sent to a City committee for a variance, which can add many months and tens of thousands of dollars, with no guarantee you win. This guide explains the limits in plain terms so you know what you can build and what would force you into a variance.

What does “as-of-right” mean for you?

It means you do not have to ask the City’s permission to build a fourplex. The zoning already allows it. You submit a building permit application showing your design follows the rules, and if it does, the City has to approve it.

That is a big deal, because the alternative is slow and expensive. If your design needs a variance, the approval can take 12 to 24 months and cost $20,000 to $50,000 or more in planning and legal fees, and it can still be refused at the end. So the entire game is designing a fourplex that fits the rules from the start, so you never have to go through that. Everything below is about staying on the safe side of that line.

What are the limits on the building?

There are really only four things that limit the size and shape of your fourplex: how tall it can be, how much of the lot it can cover, how far it has to sit from the property lines, and how deep it can go. There used to be a fifth limit, on total floor area, and the fact that it no longer applies is what makes fourplexes work. Here is each one at a glance, before we go through them in turn.

Every number here shifts with your specific zone and any site-specific exception, so treat the table as orientation and confirm your own figures. The sections below explain what each one means in practice.

How tall you can build

Most Toronto residential lots allow a building 10 to 12 metres tall, which is about three storeys. Even where the map shows a lower limit, a fourplex is allowed to reach 10 metres. Height is measured from the ground up to the peak of the roof, and on a sloped lot exactly where the City measures the ground from can gain or cost you usable height, which is worth getting right early.

How much of the lot you can cover

You are allowed to cover a set percentage of your lot with the building, usually somewhere between 30 and 50 percent depending on where you are. This is a hard limit. Even if four units would physically fit, you cannot cover more of the lot than the percentage allows. This is one of the most common reasons a design has to shrink or gets sent to the committee, so it is worth checking your number before you fall in love with a big footprint.

How far the building sits from the property lines

The building has to keep a minimum distance from each edge of your lot, called a setback. The front setback is often not a fixed number: in many neighbourhoods your front wall has to line up with the average of the houses on either side, so what your neighbours did partly decides where your house sits. The side gaps are small, often between about half a metre and just over a metre, but on a narrow lot they eat up a real share of your width. The rear setback is usually 7.5 metres, which shortens how deep you can build on a shallow lot. These distances are the same as for any house in your area; the fourplex rules did not change them.

How deep the building can go

A fourplex can be up to 19 metres deep, front wall to back wall, on a lot with room for it. This works together with the rear setback. On a lot that is 30 metres deep, once you leave 7.5 metres at the back and about 6 at the front, you have around 16.5 metres to build in. On a deeper lot you can use the full 19.

The limit that no longer applies, and why it matters

On a normal building project, the limit that usually holds you back is a cap on total floor area relative to lot size. For fourplexes, that cap does not apply. This is the single reason you can fit four units into roughly the same building size as a large single house. The only thing to watch is a site-specific exception (the City calls it Chapter 900) that can put a floor-area cap back on one particular property, so it is worth checking whether yours carries one.

Is your lot wide enough?

The rules technically allow a fourplex on a lot as narrow as 6 metres, about 20 feet. But allowed and practical are different. On a 6-metre lot, once you subtract the side gaps you are left with roughly 4.2 metres of building width, which is tight for one unit, never mind four.

Width is what decides how your units are arranged. On a narrow lot, there is not enough room to place units beside each other, so they have to stack on top of one another, one per floor. On a wider lot, you have the option of placing units side by side as well as stacking them, which opens up more layout choices and can make for larger, better-lit units. The permission is the same everywhere, a 25-foot lot has the same right to a fourplex as a 50-foot lot, but the two will produce very different buildings. Knowing which yours can support is the first practical question to answer.

Do you have to provide parking?

No. Since February 2022, Toronto requires no parking at all for a duplex, triplex, or fourplex, anywhere in the city. For most owners this is a gift: no digging for underground spaces, no driveway eating your frontage, more of the lot free to build on, and lower construction costs. You can still add parking if it suits your lot, but you do not have to. You may need to provide a couple of bicycle parking spots depending on the project, which is easy to accommodate.

What building layouts actually work?

A few arrangements reliably produce a fourplex that fits the rules:

• Stacked units: two on the ground floor and two above, or one unit per floor in a three-storey building with a basement unit. This is the go-to on a narrow lot.
• Front to back: units running from the front of the building to the rear, each with its own entrance. This suits a wider lot with good depth.
• Basement plus upper floors: a walkout basement unit with units above, using the below-grade space to get more room without going taller.

Whatever the layout, each unit needs its own kitchen, bathroom, living space, and bedroom; the walls and floors between units have to meet fire-separation rules, which are not optional; stacking kitchens and bathrooms above each other saves real money on plumbing; and every unit needs proper natural light, which is the main challenge for basement units.

Should you convert your house or tear it down and rebuild?

Both routes are open. Converting your existing house into four units is often faster and can cost less, but you are working with what is already there, and older Toronto homes usually need structural work, waterproofing, new plumbing and electrical, insulation, fire separation, and layout changes. Building new means removing the existing house and putting up a purpose-built fourplex, which gives you the best layouts and full code compliance but costs more and takes longer.

One money point that favours converting: the City does not charge development charges on a triplex or fourplex conversion, which can save a significant sum compared with a new build. The full cost picture, construction budgets, development charges, and financing, is covered in our separate guide to multiplex costs.

What sends you to the committee, and how to avoid it?

Anything that breaks one of the limits above, too tall, too much lot coverage, too close to a property line, too deep, or a site-specific restriction, means you need a minor variance before you can get a permit. That process involves fees, notifying your neighbours, a public hearing, and a decision that might approve, approve with conditions, or refuse you, with the chance of an appeal after. Figure on 3 to 6 months if nobody appeals, and $10,000 to $30,000 or more in fees and consultants.

Avoiding that is the best thing you can do for your budget and your timeline, and it comes down to designing your fourplex within the limits from the start. That is exactly what a good architect is for, and it is the core of what we do as a multiplex architect. Get the design right on the first try and your fourplex goes straight to permit.

Sara Rahgozar, M.Arch, OAA, Quadrant Architects. 416-357-5713 · sara@quadrantarchitects.com

Current as of August 2026. Zoning rules change. Verify the rules for your specific address through the City of Toronto’s Interactive Zoning By-law Map or Toronto Building Customer Service before making design or investment decisions.

How to Check Any Toronto Property’s Zoning

By Sara Rahgozar, M.Arch, OAA, Quadrant Architects

Before you sketch a line or spend a dollar on a multiplex project, you need to know what the zoning actually allows on your specific lot. Toronto’s new multiplex rules are generous, but they are not uniform. The zone, the lot dimensions, the height overlay, the ward, and whether you front a major street all change what you can build. The good news is that you can check almost all of it yourself, for free, in about half an hour.

This guide walks through how to look up any Toronto property and read what it permits, using the City’s own tools.

What tools do you need?

Three free resources cover most of what you need, and all of them are public.

The Interactive Zoning By-law Map is the main one. Enter an address and it returns the property’s zone category, height limit, lot dimensions, and any site-specific exceptions. Search the City of Toronto website for “Interactive Zoning By-law Map” to find it.

The Official Plan maps fill in two things the zoning map does not. Map 2 shows the land use designation, including whether the lot is designated Neighbourhoods, and Map 3 shows the major streets, which is what determines whether a lot qualifies for the six-storey permissions.

For precise lot dimensions, GeoWarehouse or OnLand (both Teranet services) give you frontage, depth, and area when the zoning map alone is not detailed enough.

What do the zone codes mean?

Most residential lots eligible for a multiplex fall into one of these zones under Zoning By-law 569-2013:

• R (Residential) is the broadest residential zone, found mostly in the older parts of the city, the former City of Toronto and York. It generally allows smaller setbacks, which is part of why the west-end streetcar suburbs have seen the most multiplex activity.
• RD (Residential Detached) covers most of Toronto’s detached housing, especially in North York, Scarborough, and Etobicoke. It generally carries larger setbacks and wider minimum lot widths.
• RS (Residential Semi-Detached) is for semi-detached and similar forms.
• RT (Residential Townhouse) is for townhouse-form buildings.
• RM (Residential Multiple Dwelling) permits a broader range of multi-unit forms.

All of these permit up to four units city-wide. In the nine sixplex wards, detached houseplexes of up to six units are also permitted.

How do you actually check a property, step by step?

Seven steps take you from an address to a clear picture of what is possible.

1. Enter the address on the Interactive Zoning Map

Type the address into the search bar and a box returns the zone category, the maximum height from the height overlay, the lot coverage limit, the setbacks, and any Chapter 900 site-specific exceptions. That last one matters more than people realize: a Chapter 900 exception can override the general zone rules with its own height limit, its own FSI cap, or other conditions. Always check it.

2. Confirm the Official Plan designation

The multiplex permissions apply to land the Official Plan designates as Neighbourhoods. Most RD, RS, and RT lots are in Neighbourhoods, but not all, so confirm it on Map 2. If the lot is designated Mixed Use Areas or Apartment Neighbourhoods instead, different and often more permissive rules apply.

3. Check the ward

Find which of Toronto’s 25 wards the lot is in, because it decides your unit ceiling. In the nine sixplex wards (the eight Toronto and East York district wards plus Ward 23 in Scarborough North), up to six units are allowed as-of-right. Everywhere else the maximum is four, unless the local councillor has opted in. The City’s ward finder returns the ward and councillor from an address.

4. Check Map 3 for major streets

If the lot fronts a street shown on Map 3, it may qualify for the six-storey, up-to-60-unit major streets permissions. The words that matter are “fronts onto.” The lot needs direct frontage on the major street. A lot on a side street one block back does not qualify, even if it is very close.

5. Check for a heritage designation

A property in a Heritage Conservation District, or one individually designated under the Ontario Heritage Act, can face limits on exterior changes, additions, or demolition. Heritage status does not rule out a multiplex, but it can constrain what you do to the outside and may add approvals. The City’s Heritage Property Search tells you whether an address carries a designation.

6. Measure the lot

Lot dimensions decide what physically fits inside the zoning envelope. Frontage is the width at the front property line; multiplexes are possible on frontages as narrow as 6 metres in some zones, but the design gets tight below about 7.5 metres (25 feet). Depth governs how much building you can fit between the front and the rear setback, and the 19-metre maximum building depth only helps if the lot is deep enough to use it. Area drives the lot coverage calculation. Take these from a survey, not an online estimate, and if you do not have a recent one, you will need it for the permit anyway.

7. Check for a laneway

Look at the rear of the lot. If it abuts a public laneway, a laneway suite is possible on top of the units in the main building. If it does not, a garden suite may be. The laneway has to be a public one maintained by the City, not a private drive or shared access, and the zoning map shows which laneways are public.

What does the zoning envelope look like?

Once you have the zone and the lot, the envelope comes down to a few controls. Lot coverage typically runs 30 to 50 percent depending on the zone. Height caps at 10 to 12 metres in most residential zones, and where the overlay is under 10 metres a multiplex can still reach 10. Setbacks vary by zone and lot width, with the front setback often governed by the prevailing-setback rule, meaning your front wall lines up with the average of the neighbours rather than a fixed number.

The single most useful thing to know: FSI, the floor space index that is usually the binding constraint on a build, does not apply to multiplexes unless a Chapter 900 exception imposes one. For a multiplex, the limits that actually bite are height, lot coverage, and setbacks.

What are the red flags?

A handful of things can complicate or quietly kill a multiplex project, and they are worth catching at the checking stage rather than after you have paid for drawings:

• A Chapter 900 site-specific exception that adds restrictions
• A Heritage Conservation District that limits exterior changes
• Easements or rights-of-way that eat into usable lot area
• Flood plains or other environmental constraints
• Servicing limits, since older areas can have combined sewers or undersized water mains that need upgrading
• Protected trees in the building footprint or rear yard, which matter especially for a backyard suite

The bottom line

A proper zoning check takes about 30 minutes and tells you what is possible before you spend anything on design. The City’s tools are free and open to anyone, so use them before you hire a designer, make an offer, or promise a client a unit count.

If you are working with an architect or designer, this review should be the first thing they do, and they should be able to point to the exact by-law provisions that support whatever they are proposing. It is the first step we take on any multiplex project. If you would rather have it done for you, Quadrant Architects offers a feasibility review as a multiplex architect.

Sara Rahgozar, M.Arch, OAA, Quadrant Architects. 416-357-5713 · sara@quadrantarchitects.com

Current as of August 2026. Zoning rules change. Verify the rules for your specific address through the City of Toronto’s Interactive Zoning By-law Map or Toronto Building Customer Service before making design or investment decisions.

What Is Adaptive Reuse, and When Does It Make Sense?

By Sara Rahgozar, M.Arch, OAA, Quadrant Architects

There is a building on almost every older main street in Ontario that has outlived its original purpose. A former bank, a shuttered church, an office nobody leases anymore. Buildings like these have good bones and real character, and increasingly they are being given a second life: kept, and adapted to a new use. That is adaptive reuse, and it has quietly become one of the most active areas of commercial architecture in the province.

We are doing this now with a heritage building on Main Street in Newmarket, converting a former law office into a lounge. Here is what adaptive reuse actually means, why it is worth doing, and where the real difficulty lies.

What is adaptive reuse?

Adaptive reuse is taking an existing building and converting it to a use different from the one it was built for. A factory becomes lofts. A church becomes a concert hall. An office becomes a lounge. The structure stays; the purpose changes.

It is different from restoration, which returns a building to its original state, and from renovation, which updates a building for the same use. Adaptive reuse specifically means a change of use: the building does a new job while keeping the bones, and often the character, of the old one.

Why is adaptive reuse becoming more common in Ontario?

Because older buildings hold value that is difficult and expensive to recreate, and municipalities increasingly recognize it, especially in heritage and downtown areas where the character of the street matters. Putting an existing building back into active use is often welcomed in an established main street, where a vacant or underused building is a gap the whole block feels.

There are several reasons behind the trend. Existing buildings hold what is called embodied carbon, the emissions already spent to produce their materials and construct them, and reusing a building keeps that investment rather than starting from scratch. Older buildings also carry architectural details, hand-laid brick, wood-frame structure, original proportions, that are expensive or impossible to replicate today. And bringing a building back into use returns activity to a street quickly. For a downtown trying to stay vital, that matters.

Does adaptive reuse save money?

Often, but not always, and the honest answer is that it depends on the building. Working with an existing structure can cost less and move faster than building new, because the shell, the foundation, and much of the structure are already there.

The savings are not guaranteed, though. An old building can hide problems, structure that needs reinforcing, systems that need full replacement, hazardous materials that need removal, that add cost quickly. This is why the first step in any adaptive reuse project is an honest assessment of the existing building before anyone commits. A good candidate saves money. A poor one can be more expensive than expected. Knowing which you have is the whole game.

What is the hardest part of an adaptive reuse project?

Meeting today’s building code inside a building that was designed for a different era and a different use. When the use changes, the Ontario Building Code requires the building to meet current standards for its new purpose, and older buildings rarely meet them as found.

That can mean adding exits, upgrading fire protection, reinforcing floors for heavier loads, and bringing accessibility up to current requirements, all within a structure you are trying to preserve. On the Newmarket lounge, converting an office to an assembly space meant adding a second means of egress, coordinating structural and fire-protection work, and doing it without altering the heritage storefront that made the building worth keeping. Threading modern requirements through an old building without erasing its character is the central skill in this kind of work, and it is why these projects need an architect who is fluent in both the code and the heritage side.

What makes a building a good candidate for adaptive reuse?

A few things separate a building that will convert well from one that will fight you:

• Sound structure. The bones need to be in good enough condition to build on. Structural problems are the most expensive surprises.
• A workable layout. Floor-to-floor heights, column spacing, and the depth of the building all have to suit the new use, at least reasonably.
• Character worth keeping. The whole argument for reuse is stronger when the building has features, brick, detailing, proportion, that new construction cannot match.
• A location that supports the new use. A great building in the wrong place is still the wrong place.
• A realistic code path. Some conversions are straightforward; others require variances or extensive upgrades. Knowing which before you buy is essential.

An architect can assess most of this in an early feasibility review, before a purchase or lease is committed, which is exactly when that judgment is most valuable.

Adaptive reuse and heritage architects in Ontario

Quadrant Architects works on adaptive reuse, heritage conversions, and change-of-use projects across Newmarket, Aurora, Richmond Hill, Markham, Toronto, and the wider GTA. We start with an honest read of the existing building, what it can support, what it will require, and what makes it worth keeping, so the decision to reuse is grounded in fact rather than hope. Related services: tenant improvement and change of use · hospitality architect · commercial architecture services.

If you are weighing whether an older building is worth reusing, that is exactly the question an early feasibility review answers. You can also see one of these projects in progress at our 193 Main Street South heritage lounge in Newmarket.

Sara Rahgozar, M.Arch, OAA, Quadrant Architects. 416-357-5713 · sara@quadrantarchitects.com